A Southwest Airlines flight was forced to circle Oakland, California for four hours before making an emergency landing after experiencing problems with the landing gear.KAREN BLEIER/AFP/GettyImages

A Chicago-bound Southwest Airlines flight was forced to make an emergency landing on 23 December at Oakland International Airport in California, after reportedly facing a problem with its landing gear. The Southwest 2547 flight to Chicago Midway Airport, with 139 passengers on board, flew around California's Central Valley for about four hours to burn off fuel before making its approach to the airport at 10am PST/6pm GMT.

According to CBS San Francisco, the flight departed from Oakland at 6.13am PST and immediately reported the gear problem. "After takeoff, the Captain in Command made the decision to return to Oakland to check a maintenance item on the aircraft," Southwest said in a statement.

Passengers and crew aboard the flight immediately realised after takeoff that there was a problem, CBS San Francisco reported. It was originally believed that the issue involved the engine, which the pilot believed could be fixed in minutes. However, when the landing gear was brought up following takeoff, passengers witnessed some sparks. The pilot reportedly attempted to bring the landing gear down, but it was not working.

The plane's pilot decided to fly the Boeing 737 for four hours to burn off the plane's 12,000 gallon fuel tank. The plane flew loops from Oakland to Manteca and South Stockton. Passenger Ashley Stasio said passengers were told to brace themselves upon landing, but the landing went smoothly.

"People were holding hands. Everybody was on their phones, I'm sure sending messages to their loved ones," Stasio said. "I don't mean to sound dramatic, but it was scary." The plane was escorted by firefighters and turned over to Southwest officials. According to the Chicago Sun Times, no injuries were reported, but some passengers reportedly were panicking towards the end of the incident.